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Batistatou N, Kritzer JA. Recent advances in methods for quantifying the cell penetration of macromolecules. Curr Opin Chem Biol 2024; 81:102501. [PMID: 39024686 PMCID: PMC11323051 DOI: 10.1016/j.cbpa.2024.102501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/17/2024] [Accepted: 06/24/2024] [Indexed: 07/20/2024]
Abstract
As the landscape of macromolecule therapeutics advances, drug developers are continuing to aim at intracellular targets. To activate, inhibit, or degrade these targets, the macromolecule must be delivered efficiently to intracellular compartments. Quite often, there is a discrepancy between binding affinity in biochemical assays and activity in cell-based assays. Identifying the bottleneck for cell-based activity requires robust assays that quantify total cellular uptake and/or cytosolic delivery. Recognizing this need, chemical biologists have designed a plethora of assays to make this measurement, each with distinct advantages and disadvantages. In this review, we describe the latest and most promising developments in the last 3 to 4 years.
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Affiliation(s)
| | - Joshua A Kritzer
- Department of Chemistry, Tufts University, Medford MA 02155, USA.
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2
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Batistatou N, Kritzer JA. Comparing Cell Penetration of Biotherapeutics across Human Cell Lines. ACS Chem Biol 2024; 19:1351-1365. [PMID: 38836425 DOI: 10.1021/acschembio.4c00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
A major obstacle in biotherapeutics development is maximizing cell penetration. Ideally, assays would allow for optimization of cell penetration in the cell type of interest early in the drug development process. However, few assays exist to compare cell penetration across different cell types independent of drug function. In this work, we applied the chloroalkane penetration assay (CAPA) in seven mammalian cell lines as well as primary cells. Careful controls were used to ensure that data could be compared across cell lines. We compared the nuclear penetration of several peptides and drug-like oligonucleotides and saw significant differences among the cell lines. To help explain these differences, we quantified the relative activities of endocytosis pathways in these cell lines and correlated them with the penetration data. Based on these results, we knocked down clathrin in a cell line with an efficient permeability profile and observed reduced penetration of peptides but not oligonucleotides. Finally, we used small-molecule endosomal escape enhancers and observed enhancement of cell penetration of some oligonucleotides, but only in some of the cell lines tested. CAPA data provide valuable points of comparison among different cell lines, including primary cells, for evaluating the cell penetration of various classes of peptides and oligonucleotides.
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Affiliation(s)
- Nefeli Batistatou
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Joshua A Kritzer
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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An SI-traceable reference material for virus-like particles. iScience 2022; 25:104294. [PMID: 35573192 PMCID: PMC9095743 DOI: 10.1016/j.isci.2022.104294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/06/2022] [Accepted: 04/20/2022] [Indexed: 11/24/2022] Open
Abstract
A reference material for virus-like particles traceable to the International System of Units (Système International d'Unités – the SI) is reported. The material addresses the need for developing reference standards to benchmark virus-like gene delivery systems and help harmonize measurement approaches for characterization and testing. The material is a major component of synthetic polypeptide virus-like particles produced by the state-of-the-art synthetic and analytical chemistry methods used to generate gene delivery systems. The purity profile of the material is evaluated to the highest metrological order demonstrating traceability to the SI. The material adds to the emerging toolkit of reference standards for quantitative biology. A reference material for virus-like particles with traceability to the SI The material is a major component of virus-like particles capable of gene delivery Purity profile of the material is evaluated to the highest metrological order The material allows comparability of physicochemical properties of virus-like systems
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Vila-Gómez P, Noble JE, Ryadnov MG. Peptide Nanoparticles for Gene Packaging and Intracellular Delivery. Methods Mol Biol 2021; 2208:33-48. [PMID: 32856254 DOI: 10.1007/978-1-0716-0928-6_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Efficient gene transfer is necessary for advanced biotechnologies ranging from gene therapy to synthetic biology. Peptide nanoparticles provide suitable packaging systems promoting targeted gene expression or silencing. Though these systems have yet to match the transfection efficacy of viruses, they are typically devoid of drawbacks characteristic of virus-based vectors, including insertional mutagenesis, low packaging capacities, and strong immune responses. Given the promise nanoparticle formulations hold for gene delivery, methods of their preparation and accurate analysis of their physicochemical and biological properties become indispensable for progress toward systems that seek to outperform viral vectors. Herein, we report a comprehensive protocol for the preparation and characterization of archetypal peptide nanoparticles resulting from nonspecific and noncovalent complexation with RNA and DNA.
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Affiliation(s)
| | - James E Noble
- National Physical Laboratory, Teddington, Middlesex, UK
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Abstract
Approximately 75% of all disease-relevant human proteins, including those involved in intracellular protein-protein interactions (PPIs), are undruggable with the current drug modalities (i.e., small molecules and biologics). Macrocyclic peptides provide a potential solution to these undruggable targets because their larger sizes (relative to conventional small molecules) endow them the capability of binding to flat PPI interfaces with antibody-like affinity and specificity. Powerful combinatorial library technologies have been developed to routinely identify cyclic peptides as potent, specific inhibitors against proteins including PPI targets. However, with the exception of a very small set of sequences, the vast majority of cyclic peptides are impermeable to the cell membrane, preventing their application against intracellular targets. This Review examines common structural features that render most cyclic peptides membrane impermeable, as well as the unique features that allow the minority of sequences to enter the cell interior by passive diffusion, endocytosis/endosomal escape, or other mechanisms. We also present the current state of knowledge about the molecular mechanisms of cell penetration, the various strategies for designing cell-permeable, biologically active cyclic peptides against intracellular targets, and the assay methods available to quantify their cell-permeability.
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Affiliation(s)
- Patrick G. Dougherty
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
| | - Ashweta Sahni
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
| | - Dehua Pei
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
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Deprey K, Becker L, Kritzer J, Plückthun A. Trapped! A Critical Evaluation of Methods for Measuring Total Cellular Uptake versus Cytosolic Localization. Bioconjug Chem 2019; 30:1006-1027. [PMID: 30882208 PMCID: PMC6527423 DOI: 10.1021/acs.bioconjchem.9b00112] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Biomolecules have many properties that make them promising for intracellular therapeutic applications, but delivery remains a key challenge because large biomolecules cannot easily enter the cytosol. Furthermore, quantification of total intracellular versus cytosolic concentrations remains demanding, and the determination of delivery efficiency is thus not straightforward. In this review, we discuss strategies for delivering biomolecules into the cytosol and briefly summarize the mechanisms of uptake for these systems. We then describe commonly used methods to measure total cellular uptake and, more selectively, cytosolic localization, and discuss the major advantages and drawbacks of each method. We critically evaluate methods of measuring "cell penetration" that do not adequately distinguish total cellular uptake and cytosolic localization, which often lead to inaccurate interpretations of a molecule's cytosolic localization. Finally, we summarize the properties and components of each method, including the main caveats of each, to allow for informed decisions about method selection for specific applications. When applied correctly and interpreted carefully, methods for quantifying cytosolic localization offer valuable insight into the bioactivity of biomolecules and potentially the prospects for their eventual development into therapeutics.
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Affiliation(s)
- Kirsten Deprey
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States
| | - Lukas Becker
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Joshua Kritzer
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Whiting G, Ferguson J, Fang M, Pepin D, Donahoe P, Matejtschuk P, Burns C, Wheeler JX. Quantification of Müllerian Inhibiting Substance/Anti-Müllerian Hormone polypeptide by isotope dilution mass spectrometry. Anal Biochem 2018; 560:50-55. [PMID: 29742446 DOI: 10.1016/j.ab.2018.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/04/2018] [Accepted: 05/04/2018] [Indexed: 10/16/2022]
Abstract
Measurement of serum concentrations of Müllerian inhibiting substance (MIS), also known as anti-Müllerian Hormone (AMH) by immunoassay is gaining clinical acceptance and widespread use for the diagnosis of ovarian conditions and for prediction of the response to ovarian stimulation protocols as part of assisted reproductive therapies. Provision of an International Standard to harmonize immunoassay methods is required. It is desirable for the content of a future International Standard to be assigned in mass units for consistency with the units reported by current methods. Isotope dilution mass spectrometry (IDMS), a physicochemical method with traceability to the SI (Système International d'Unités) unit of mass, is a candidate approach to provide orthogonal data to support this mass assignment. Here, we report on the development of an IDMS method for quantitation of AMH using three peptides from different regions of the AMH monomer as surrogates for the measurement of AMH. We show the sensitivity and linearity of the standard peptides and demonstrate the reproducibility and consistency of the measurement amongst the three peptides for determining the AMH content in buffered preparations and in trial preparations of recombinant AMH, lyophilised in the presence of an excess of bovine casein.
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Affiliation(s)
- Gail Whiting
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK.
| | - Jackie Ferguson
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK
| | - Min Fang
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK
| | - David Pepin
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, 185 Cambridge Street, CPZN 6206, Boston, MA02114, USA
| | - Patricia Donahoe
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, 185 Cambridge Street, CPZN 6206, Boston, MA02114, USA
| | - Paul Matejtschuk
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK
| | - Chris Burns
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK
| | - Jun X Wheeler
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, EN6 3QG, UK
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Abstract
A synthetic topology for everted viruses is reported. The topology is a single-stranded virion DNA assembled into a hollow cube with exterior decorated with HIV-Tat transduction domains. The cube incorporates a pH-responsive lid allowing for the controlled encapsulation of functional proteins and their transfer and release into live cells. Unlike viruses, which are protein shells with a [3,5]-fold rotational symmetry that encase nucleic acids, these cubes are [3, 4]-fold DNA boxes encapsulating proteins. Like viruses, such everted DNA-built viruses are monodisperse nanoscale assemblies that infect human cells with a specialist cargo. The design offers a bespoke bottom-up platform for engineering nonpolyhedral, nonprotein synthetic viruses.
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Affiliation(s)
- Jonathan R. Burns
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, U.K
- Department of Chemistry, University College London, London, WC1E 6BT, U.K
| | - Baptiste Lamarre
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, U.K
| | - Alice L. B. Pyne
- London Centre for Nanotechnology, University College London, London, WC1E 6BT, U.K
| | - James E. Noble
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, U.K
| | - Maxim G. Ryadnov
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, U.K
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Chiu JZS, Tucker IG, McDowell A. Quantification of Cell-Penetrating Peptide Associated with Polymeric Nanoparticles Using Isobaric-Tagging and MALDI-TOF MS/MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1891-1894. [PMID: 27629919 DOI: 10.1007/s13361-016-1486-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 06/06/2023]
Abstract
High sensitivity quantification of the putative cell-penetrating peptide di-arginine-histidine (RRH) associated with poly (ethyl-cyanoacrylate) (PECA) nanoparticles was achieved without analyte separation, using a novel application of isobaric-tagging and high matrix-assisted laser desorption/ionization coupled to time-of-flight (MALDI-TOF) mass spectrometry. Isobaric-tagging reaction equilibrium was reached after 5 min, with 90% or greater RRH peptide successfully isobaric-tagged after 60 min. The accuracy was greater than 90%, which indicates good reliability of using isobaric-tagged RRH as an internal standard for RRH quantification. The sample intra- and inter-spot coefficients of variations were less than 11%, which indicate good repeatability. The majority of RRH peptides in the nanoparticle formulation were physically associated with the nanoparticles (46.6%), whereas only a small fraction remained unassociated (13.7%). The unrecovered RRH peptide (~40%) was assumed to be covalently associated with PECA nanoparticles. Graphical Abstract ᅟ.
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Affiliation(s)
- Jasper Z S Chiu
- School of Pharmacy, University of Otago, 18 Frederick Street, Dunedin, 9016, New Zealand
| | - Ian G Tucker
- School of Pharmacy, University of Otago, 18 Frederick Street, Dunedin, 9016, New Zealand
| | - Arlene McDowell
- School of Pharmacy, University of Otago, 18 Frederick Street, Dunedin, 9016, New Zealand.
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